The Chicago parolee suspected of murdering three of Oscar-winner Jennifer Hudson’s relatives was busted in June for cocaine possession – but officials failed to lock him back up for the parole violation, it was revealed yesterday.

A parole agent had contacted the suspect, William Balfour, last Friday for missing a required meeting at around the same time that the bodies of Hudson’s mom and brother were discovered in their South Side home.

Balfour, 27, was busted hours later in the slayings of Hudson’s mom and brother. At the time, Hudson’s nephew, 7-year-old Julian Hudson, was missing from the murder scene.

Julian, who was Balfour’s stepson, was found dead of multiple gunshots Monday morning in an abandoned SUV.

Balfour had been free on parole after serving seven years in prison for an attempted murder and carjacking.